Heating unit.



W. H. DALTON.

HEATING UNIT.

APPLICATION FILED on. 22. I915.

Patented July 10, 1917.

Fig. 3.

InvenTor. William H. DulTon b fmzww' UNITED STATES PATENT OFFICE.

WILLIAM H. DALTON, OF SALEM, MASSACHUSETTS, ASSIGNOR TO WILLIAM H. DALTON 00., OF SALEM, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

HEATING UNIT.

Application filed October 22, 1915.

To all whom it may concern:

Be it known thatI, WILLIAM H. DALTON,

a citizen of the United States, residing at Salem, county of Essex, State of Massachusetts, have invented an Improvement in Heating Units, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to electrical-heating units and particularly to a Hat heating unit, and the principal object of the invention is to provide a novel heating unit having a flat shape which can be inexpensively manufactured, which can be made very thin without impairing its efficiency, which is constructed to provide a plurality of difier ent heats or temperatures, and which has other advantageous features, all as will be more fully hereinafter described.

In order to give an understanding of my invention I have illustrated in the drawing a selected embodiment thereof which is es pecially designed for use in connection with an embossing block, such as is used in hot embossing machines, although I desire to state that the invention is not limited in its use to embossing blocks, but is capable of use generally where a fiat heating element is required.

In the drawings, Figure 1 is-a plan view of a heating element embodying my invention;

Fig. 2 is a section on the line 2-2, Fig. 1;

Fig. 3 is a section on the line 33, Fig. 2, said figure also showing a controlling switch by which the temperature developed by the heating unit may be regulated.

In order to provide a heating unit which can be cheaply and inexpensively manufactured, I propose to make my improved heat ing unit with an annular frame member which constitutes the-edge walls of the chamberin which the heating coils are received and with two side or face plates which are secured to the frame and which form the top and bottom faces of the unit. The annular frame is shown at 1 and is illustrated in the drawing as a rectangular frame. 2 and 3 designate the face plates that are secured to the frame 1 and form with it the chamber for receiving the heating coil. The plate 2 is a thinsheet metal plate which is Specification of Letters Patent.

Patented July 10, 1917.

Serial No. 57,354.

secured to the frame 1 in any suitable way, as by means of screws 4. The plate 3 is also a comparatively thin sheet metal plate which overlies the opposite side of the frame 1 and is secured thereto by screws 5. The heating coil or coils are confined in the space or chamber formed by the frame 1 and the plates 2 and 3. I will preferably fill the chamber thus formed with a suitable cement 6 in which the coils are laid. This cement will have both insulating and heatconducting properties, so that it will operate to insulate the turns of the coils from each other and form the frame 1 and plates 2 and 3, but at the same time will operate as means for readily conducting the heat of the coils to the surfaceof the unit. Any suitable cement havingthese properties may beused.

Any suitable arrangement of heating coils may be=used,.depending onthe use to which the heating unit is-to be put. In the construction herein illustrated I have shown a heating. coil constructed to develop three dilferent temperatures, that is, a comparatively low temperature, a medium temperature, and a comparatively high temperature. I accomplish this by providing two coils, one of which is so wound and has such a resistance as to develop a comparatively low temperature, and the other of which is so wound and has such a resistance as to develop a higher or medium temperature. When the low temperature coil is used, the desired low temperature will be produced. When the other coil is used, a medium temperature will be produced. In order to develop a high temperature, both coils are used; The low temperature coil is shown at 7, and the other coil at 8. The coil 8 is illustrated as comprising two members connected in parallel, but a coil of any construction may be used.

The heating unit is provided with three terminals 9, 10 and 11. The terminal 9 1s connected'by a wire 12 with both of the coils 7 and 8. 'Tlic terminal 10 is connectedby a wire 13 with the coil 7, .while the terminal 11 is connected by the wire 14 with the coil 8. When the electric-circuit whichsupplies current to the heating unit is connected to the two terminals 9 and l0,'then thelow temperature coil 7 only will-be operated and the low temperature will be develop d. It the supply circuit is connected to the terminals 9 and 10, then the other coil 8 will become operative to develop a higher temperature. By connecting one side of said supply circuit to the terminal 9 and the other to both terminals 10 and 11, then the maximum heat will be produced since both coils will be activesimultaneously. The heating unit as thus far described is capable of use in a variety of ways where a flat heating unit is desirable. The particular construction herein illustrated has provision for detachably securing to one face thereof an impression die, such as would be used in hot embossing or in printing or stamping leather, cloth or other goods. This is provided for herein by detachably securing to one face of the unit a holding plate to which impression dies of different sizes and shapes may be readily secured. The holding plate isshown at 15 4 and it overlies the plate 2. Said late 15 is secured tothe unit in any suitab e way, as by means of screws 16 at the corners thereof, which screw into apertures 17 in the frame 1. This plate 15 is provided with a plurality of tapering apertures 18, each of a size to receive the tapered head of an ordinary screw, said apertures being formed with the smaller end thereof on the exposed side of the plate 15 and the larger end on the side which contacts with the plate '2.

19 is an impression die on which are formed suitable type characters 20. This die is secured to the plate 15 by means of screws 21 that are entered through certain of the apertures 18. The die 19 will have to be attached to the plate 15 when the latter is removed from the heating unit, and after the die has been properly attached by the screws 21, then the plate 15 can be secured :to the heating unit by its screws 16. The heads of the screws 21 come flush with the plate 15 and fill the apertures 18. When the plate 15 is secured to the heating unit, the screws 21 are entirely protected and are prevented from wearing loose and are also concealed so that they form no projections that are likely to affect in any way the embossing or printing operation. I propose to make the plate 15 with a plurality of apertures 18 so as to permit impression dies 19 of different sizes to be readily applied thereto, and also so as to permit the die 19 to be attached to the plate 15 in different positions. A heating unit having this construction can be made type high so that it can be set into i the form used in a printing press and constitute partof the type of the form.

The operation of printing involves the application of considerable pressure to the type, and in order to prevent any injzury to the coils or any yielding of the plates 2 and 3 of the heating unit, I propose to introduce one or more filling or reenforcing bars 23 between the plates :2 and 3 and to which said plates may be secured. These reenforcing or llin bars will be placed between the coils 7 an 8 so as not to interfere with them.

In order to provide a certain amount of heat insulation between the heating unit and the platen on which it rests, I propose to secure to the underside of the unit an insulatin plate 24 of sheet metal which is provided with a plurality of openings 25 that constitute air pockets. These pockets or openings 25 constitute a sort of dead-air space which retains suflicient. air to heat-' insulatethe heating unit from the platen to a certain extent. My improved heating unit can be very inexpensively manufactured and can be made so thin that it has .a thickness no greater than the height ofordinary type.

I have shown in Fig. 3 a switch device by which either one or both of the heating coils can be connected. to the supply circuit. This switch device comprises a switch blade 30 adapted to connect the contacts 31 and 32, respectively, and another switch blade 33 adapted to connect the two contacts as and 35. Each pair of contacts is sustained on a suitable insulating support 36. One side of the supply circuit 38 is connected to a terminal 37 which turn is connected to the terminal 9 of the heating element. The

other side of the suupply circuit 38 is connected to a'ter'minal 39 which is associated with the contact 32 and is connected by the wire 49 with the contact 35. "The contact-31 has a terminal 41- which is connected by a wire 42 to the terminal 10, and the contact 34 is connected by a wire 43 to the terminal 11. When the switch 30 is closed, then a circuit will be completed through the coil 7 and the minimum temperature will be developed. When the switch 30 is opened and the switch 33 closed, a circuit will be established through the coil 8 and the edium temperature will be developed. When both switches are closed, then both coils are connected to the supply circuit and :themaximum temperature will be developed.

While I have illustrated herein a selected I unit, the combination with an annular ame, .of face plates secured to opposite sides of said frame and forming with the latter a chamber to receive the heating coil, a heating coil in said chamber, means within the chamber for insulating the coil from the frame, a plate removably secured to one of said face plates, and an element to be heated attached to said removable plate.

3. In a heating unit, the combination with an annular frame, of face plates secured to opposite sides of said frame and forming with the latter a chamber to receive a heating coil, a heating coil in said chamber, a plate overlying one of the face plates and removably secured to the frame, said latter plate having a plurality of tapered holes, each of a size to receive a. screw head, and an impression die secured to said apertured plate by screws which have their heads 0c cupying certain of said apertures.

4 In a Hat heating unit, the combination with a rectangular frame, of two face plates secured to opposite sides of the frame, a heating coil within the frame between the face plates, a holding plate overlying one of the face plates and detachably secured thereto, an impression die overlying the holdin late, and concealed screws securing said impression die to the holding plate.

5. In a heating unit, the combination with an annular frame, of two face plates secured to opposite sides of said frame and forming therewith a chamber to receive a heating coil, a heating coil in said chamber, an element to be heated, means for detachably securing said element to one side of said heating unit, and an apertured plate secured to the other side of said heating unit and constituting a heat-insulating element.

In testimony whereof, I have signed my name to this specification.

WILLIAM H. DALTON.

Copies 01 this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

